This invention relates to such a picture mapping apparatus and such a picture mapping apparatus to decode code word obtained by carrying out iterated transform encoding with respect to picture to restore picture to apply mapping (so-called texture mapping) to the restored picture with respect to polygon having three-dimensional shape, and a picture generation apparatus and a picture generation method for generating picture utilized for its mapping.
As a conventional representative picture compression system, so-called JPEG (Joint Photographic Coding Experts Group) standardized by ISO is known. As this JPEG system, in the case where DCT (Discrete Cosine Transform) is used so that relatively many bits are allocated, it is known to provide satisfactory encoded/decoded picture. However, when the number of bits to be encoded is lessened to some degree, block distortion peculiar to DCT becomes conspicuous so that degradation becomes conspicuous from a subject point of view.
Apart from this, in recent years, picture compression system utilizing Iterated Function Systems (IFS) begins to be remarked. This system is system such that in the case where a portion of its picture is taken out among the entirety of the picture, it utilizes auto self-analogousness of picture on the premise that another picture similar to picture which has been taken out exists in the form of different sizes among its picture. This repeat transform system is such that block distortion as in the above-described JPEG does not conspicuous, and, since self-analogousness between blocks of different sizes within picture is utilized, there is the merit that it does not depend upon resolution at the time of decoding. This iterated transform encoding is also called fractal encoding as another name, and it is expected that this encoding system is applied to various fields.
For example, there is known the technology that, e.g., function capable of restoring picture by less information quantity that fractal has is applied to the game machine. This technology will now be described with reference to FIG. 1.
The game machine shown in this FIG. 1 is of a structure such that CPU 50, work RAM 51, ROM 52, external I/F (interface) 53, fractal picture painting (drawing) section 55, GC (Graphic Display Controller) 57 and KB (Key board) I/F 60 are connected to system bus 62, and data from the game ROM 54 is read out through the external I/F 53. In addition, VRAM 56 is connected to the fractal picture drawing section 55 and the GC 57, CRT 59 is connected to the GC 57 through graphic I/F 58, and keyboard 61 is connected to the KB (Keyboard) I/F 60.
The operation thereof will now be described.
The game ROM 54 is attached to the external interface 53. When power is turned ON by operation of the power supply switch, the CPU 50 reads out, by a predetermined quantity thereof, the leading portion of the game software from the game ROM 54 to store it into the work RAM 51 to transfer initial (initialization) picture included therewithin to the GC 57. The GC 57 develops initialization picture which has been transferred onto the VRAM 56 and reads out such picture at a fixed period to transfer it to the graphic interface 58 to thereby output it to the CRT59. When the CPU 50 receives command that user has turned ON through the keyboard interface 60 from the keyboard 61, it reads out graphic data corresponding thereto from the work RAM 51 in accordance with this command to transfer it to the GC 57, or to produce movement command of display graphic, etc. to the GC 57.
In the game software which has been read out through the external interface 53 from the game ROM 54 and has been stored into the work RAM 51, fractal picture drawing command is included in addition to the conventional control program or graphic data. This fractal picture drawing command consists of numerical expression (algorithm) in which rule of graphic generation is determined and initial value relating to start position, etc. of generated graphic. The CPU 50 is operative so that when data which has been read out from the work RAM 51 in accordance with command, etc. which has been turned ON from the keyboard 61 is not graphic data, but is fractal picture painting (drawing) command, it transfers such command to the fractal picture painting (drawing) section 55 in place of the GC 57. At the fractal picture drawing section 55 which has received it, graphic elements such as line segments, etc. are generated in succession in accordance with the initial value and the numeric expression to develop them onto the VRAM 56 to thereby paint or draw various graphics, e.g., graphic of natural matter such as mountain, tree or leaf, etc. or character, etc. As described above, it is possible to draw complicated graphic of large data quantity in accordance with fractal picture drawing command of small data quantity.
Meanwhile, in the above-described background technology (art), since fractal is outputted by picture drawing command, graphic which can be painted (depicted) is limited. In addition, since the above-described background technology has not function for compressing/restoring general natural picture, there was the problem that it is limited to pictures which can be represented.
In addition, apart from the above-described technology, as the compression (encoding) technique for texture (picture) in carrying out texture mapping to object shape frequently used at the personal computer or the game machine at present, the JPEG system is used. For this reason, there were the problems that since apparent or seeming resolution of texture is improved at the time of zooming of the object shape, degradation of picture becomes conspicuous and/or sharpness of picture is lost so that obscure picture is displayed.
This invention has been made in such actual circumstances and its object is to provide a picture mapping apparatus and a picture mapping method in which picture of texture is difficult to be degraded when shape of object in which texture of general natural picture is mapped is deformed at zooming, etc. and a picture generation apparatus and a picture generation method for generating picture utilized in such mapping.
In order to solve the above-described object, this invention is characterized in that picture data which has been caused to undergo repetitive transform encoding while implementing scaling thereto to implement mapping to the repeat transform decoded decode picture with respect to picture with respect to object shape obtained while implementing scaling thereto.
Namely, the picture mapping apparatus and the picture mapping method according to this invention are characterized in that iterated transform decoding is carried out while implementing scaling to picture data which has been caused to undergo repeat transform encoding to temporarily preserve decoded picture from the repeat transform decoding unit into the buffer memory to carry out scaling of shape of a predetermined object to calculate the scaled shape of the object to implement mapping to decoded picture with respect to the scaled shape of the object.
Moreover, in the picture mapping apparatus and the picture mapping method according to this invention, picture data which has been caused to undergo repeat transform encoding consists of block No. indicating position of block and transform parameter, and the decoded picture is generated by reproducing transform source block on the basis of block No. to reproduce block located at a predetermined position to carry out scaling of the block to generate block which has been caused to undergo scaling (which will be simply referred to as scaled block as occasion may demand) to implement transform processing corresponding to conversion parameter to block picture corresponding to the scaled block to execute, a predetermined number of times, the transform decoding operations.
Further, in the picture mapping apparatus and picture mapping method in this invention, repeat transform encoded picture data consists of block No. indicating position of block and conversion (transform) parameter, and decoded picture is generated by reproducing transform original block on the basis of block No. to reproduce block located at a predetermined position to carry out scaling of block to generate scaled block to implement transform processing corresponding to conversion (transform) parameter to block picture corresponding to the scaled block to determine degree of convergence between current decode picture obtained by carrying out repetitive transform decoding and decoded picture already decoded with respect to the current decoded picture to repeatedly execute the transform decoding operation on the basis of the result thereof
Further, in the picture mapping apparatus and the picture mapping method in this invention, decoded picture finally obtained by carrying out iterated transform decoding is temporarily preserved into the buffer memory.
In addition, in the picture mapping apparatus and the picture mapping method in this invention, in carrying out iterated transform decoding, respective decode pictures obtained by respective transform decoding operations are temporarily stored in succession or sequence into the buffer memory to carry out mapping of respective decoded pictures obtained by respective transform decoding operations from the buffer memory so that shapes of objects which have been caused to undergo scaling in succession are provided.